Water contamination in the bearing lubricating oil of steam turbines causes significantly greater wear and maintenance costs for the operator/owner. When water is removed through static coalescence or mechanically by centrifuging, it is fairly common to encounter concentrations of nearly 100% water. Water concentrations above 0.5% are not effectively removed by either method and can cause premature failure in the coalescing elements. To handle such situations today, a technician must manually drain the sump until he or she feels the water concentration can be handled by the method being used. In addition to the expense of the technician and lost oil, there are the costs for disposing of the oil/water mixture properly, the environmental costs for the oil entering the sewage system, or the cost of conditioning the lubricating oil at a remote station.
One attempt to overcome these drawbacks and provide on site processing of oil is disclosed in U.S. Pat. No. 4,892,667 issued Jan. 9, 1990 to Parker, III et al. In this system, a lubricating oil processing unit is provided in which the oil is first filtered to remove some of the free water and also entrained particulate matter, and passed through a coalescing unit for final and complete free and emulsified water removal, and finally a polishing filter for complete removal of entrained particulate matter and returned to the lubricating oil reservoir. The unit provides continuous processing of lubricating oil as the oil is used, that is, as it is pumped under pressure through the turbine bearings and is returned to the reservoir. In the first filter, particulate matter is removed. Also, a significant portion of the free water is separated from the oil. In other words, this serves as a preconditioning unit. The oil from this unit is then passed to a coalescing unit where the remaining free water and the water/oil emulsion is broken by passing the oil containing the emulsion through a series of materials with the first material providing very minute interstices to initiate coalescence and then passing the oil containing the water freed by coalescence outwardly through a series of different materials until the freed water progressively forms into droplets large enough to be separated by gravity or by the separator filter element from the stream of oil.
While this system has been generally satisfactory for on site processing of oil having particular ranges or parameters of viscosities, temperatures, pressures, and water concentrations, it can be appreciated that this arrangement must utilize three discrete components provided with different types of filters to attain its goal. In particular, the coalescing unit of this system depends upon a pleated filter medium, plural layers of compressed glass fiber in mat form, a non-wettable screen, a non-compressed layer of glass fibers and a closely woven jacket of non-wettable fabric before the oil is sent to a final polishing unit containing a multilayered filter medium.
Notwithstanding this and other previous designs, it remains desirable to provide an improved turbine oil purification and conditioning apparatus of a modified type from that shown in the aforementioned prior art which is effective to remove large volumes of water concentrations and solid contaminants in turbine lubricating oil and simultaneously eliminate excessive maintenance demands and premature equipment failure. It is also highly desirable to provide an apparatus capable of purifying and conditioning oil in large volumes and removing a much higher percentage of water from the oil using a singular vessel with a simplified filter assembly. It is likewise desirable to provide a turbine oil purification and conditioning apparatus having various monitoring, control, recording and various pumping devices which will heighten the efficiency of the apparatus.